[SCSI] dm mpath: propagate target errors immediately

DM now has more information about the nature of the underlying storage
failure.  Path failure is avoided if a request failed due to a target
error.  Instead the target error is immediately passed up the stack.

Discard requests that fail due to non-target errors may now be retried.

Errors restricted to the path will be retried or returned if no
paths are available, irregarding the no_path_retry setting.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 10 insertions, 12 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index b82d28819e2a..4b0b63c290a6 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1283,24 +1283,22 @@ static int do_end_io(struct multipath *m, struct request *clone,
         if (!error && !clone->errors)
                 return 0;       /* I/O complete */
 
-        if (error == -EOPNOTSUPP)
-                return error;
-
-        if (clone->cmd_flags & REQ_DISCARD)
-                /*
-                 * Pass all discard request failures up.
-                 * FIXME: only fail_path if the discard failed due to a
-                 * transport problem.  This requires precise understanding
-                 * of the underlying failure (e.g. the SCSI sense).
-                 */
+        if (error == -EOPNOTSUPP || error == -EREMOTEIO)
                 return error;
 
         if (mpio->pgpath)
                 fail_path(mpio->pgpath);
 
         spin_lock_irqsave(&m->lock, flags);
-        if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m))
-                r = -EIO;
+        if (!m->nr_valid_paths) {
+                if (!m->queue_if_no_path) {
+                        if (!__must_push_back(m))
+                                r = -EIO;
+                } else {
+                        if (error == -EBADE)
+                                r = error;
+                }
+        }
         spin_unlock_irqrestore(&m->lock, flags);
 
         return r;